Has anybody tried pure synthetic N,N-DMT and how it compares to mimosa extract from one's perspective? Once SWIM's got a synthetic sample derived from Speeter-Anthony tryptamine synthesis, and it was significantly more powerful than visually pure extracted material. Also, it has much more pleasant odor.

I believe it is because of NMT and some other mimosa alkaloids that cannot be removed by A/B. I wonder if anybody tried treating mimosa extract with acetic anhydride, as it described in Shulgin's DET synthesis, to remove the monomethylated impurity.

Why should it be different?

DMT is DMT. Indeed impurities would be one possibility, but for example if you look at TIHKAL, one of the synth routes also can have NMT as impurity, so depending how it was cleaned up it could be similar.

But even if one had used acetic anhydride to remove NMT completely in the synthesis but this wasnt used in the extraction, if you check burnt's analysis, it shows common white crystal dmt extracted from A/B to be around 98% pure. Do you think 2% impurities of NMT / 2MTHBC / fatty acids could affect the experience so much?

The first thing i would consider to account for your experience is something else, so I turn it back to you with a question: Was it a blind test? If not, if you ever come across that sample again, would you be willing to do a blind test? I would suspect self suggestion at work.

Regarding odor, I think most odor from common A/B's is from solvent remains. Just crystallize converted freebase from dmt fumarate in water and you'll see what I mean, its definitely much more pleasant than typical petrochem-extracted dmt.